Powershift reversing gearbox

ABSTRACT

In a powershift multi-gear transmission ( 1 ), the countershafts of the reverse gear (KR), of the forward gear (KV) and of the fourth gear (K 4 ) are combined to form one reversing transmission unit ( 33 ) and the countershaft units of the first gear (K 1 ), of the second gear (K 2 ) and of the third gear (K 3 ) are combined to form one gear transmission unit ( 34 ). The reversing transmission unit ( 33 ) is provided on any side of the input shaft ( 3 ). The gear transmission unit ( 34 ) attaches to the reversing transmission unit ( 33 ) so that the reversing transmission unit ( 33 ) and the gear transmission unit ( 34 ) are disposed in relation to the input shaft ( 3 ) in succession upon one side of the input shaft ( 3 ). The gear transmission unit ( 34 ) is preferably located on the countershaft unit of the reverse gear (KR).

[0001] According to the preamble of claim 1 this invention relates to amultiple gear reversing transmission shiftable under load forconstruction machinery.

[0002] Those reversing transmissions are used in many different vehiclesin the branch of construction machinery. Typical examples of use are inexcavator loaders, fork lift trucks, wheel loaders, material handlingmachines and also mobile cranes. The multiplicity of vehicles in thisfield demands a great measure of adaptability of the transmission used,since the installation conditions in the different vehicles can turn upin the most varied ways.

[0003] The installation space available, for example, can turn out to beextremely small. Different center distances between the transmissioninput shaft and the transmission output shaft can also appear. Dependingon the type of vehicle, a specific center distance is accordingly neededbetween the input and output shafts of the transmission. Besides, inmost areas of use, at least one auxiliary drive is needed, for example,for the hydraulic system of the mobile machine. The functions that areversing transmission has to perform are, therefore, very differentlyconditioned by the type of construction of the vehicle. The requirementsmust be met within the axial length and width of the transmission.

[0004] In EP 0 759 129 B1, a powershift reversing transmission was madeknown which, by virtue of the distribution of the gear clutches, fixedgears and idler gears among several countershafts, has an input gear setand a distributor gear set with which long and short center distancescan be implemented. For long center distances, it is provided to situatethe countershafts essentially between the input and the output shafts.Depending on the gear desired, different combinations of countershaftstake part here in the transmission of power. In the case of short centerdistances, the countershafts are positioned in the circle around theinput shaft whereby their position, relative to each other, is alreadypredetermined. In the reversing transmission shaft arrangementsdifferent from each other are accordingly provided to implementdifferent center distances.

[0005] The problem on which this invention is based is to provide apowershift multi-gear reversing transmission that is adaptable todifferent installation situations, that has a shaft arrangement adequatefor bridging different center distances and that requires only a fewadditional parts in the adaptation to a certain installation situation.

[0006] On the basis of a reversing transmission of the kind described indetail above, this problem is solved with the features stated in thecharacteristic part of the claim.

[0007] The invention provides that the individual shafts of thereversing transmission be combined to form a transmission unit (KV, KR,K4) and a gear transmission unit (K1, K2, K3), the reversingtransmission unit being provided in any side of the input shaft and thegear transmission unit being attached to the reversing transmission unitso that related to the input shaft the reversing transmission unit andthe gear transmission unit is disposed in succession on one side of theinput shaft.

[0008] The countershaft units can be comprised, for example, of acountershaft, a shifting device and idle and fixed gears. The reversingtransmission unit consists of the countershaft unit for the forwardgear, the reverse gear and the fourth gear. The gear transmission unitconsists of the countershaft units for the first, the second and thethird gear. The reversing transmission unit is preferably provided onany place of the periphery of the input shaft while the geartransmission unit is attached to the countershaft unit of the reversegear.

[0009] In this manner, the shafts of the reversing transmission unit andthe input shaft, the same as the shafts of the gear transmission unitand the shaft of the reverse gear, are respectively disposed to form arectangle. The angles of the rectangle can be changed according to themomentary requirements of the specific installation situation.

[0010] By the shaft arrangement of the inventive shaft transmission, itis possible to implement both short and long center distances without itbeing needed to change the relative position to each other of theindividual shafts. Only by variation of the distances between theindividual shafts and of the angles formed by the connecting linesbetween two shafts is it possible to consider special standards of acertain vehicle type.

[0011] The flexible arrangement of the shafts can be attained without itbeing necessary to exchange the components that take part in the powerflow. A maximum of possibilities for re-use of components is thusensured.

[0012] According to a preferred embodiment of the invention, next to theinput shaft, the reversing transmission has an auxiliary output such asa PTO. The installation of the PTO is made possible since, by virtue ofthe inventive arrangement of both transmission units on one side of theinput shaft, there still is sufficient place for a PTO next to the inputshaft. An engine-dependent auxiliary output is preferably used.

[0013] For vehicles that required from the transmission the bridging ofstill greater distances, a long distance variant can be provided such ascan be implemented with a power divider transmission.

[0014] In another preferred embodiment of the invention, thecountershaft unit of the fourth gear is placed next to the input shaftindependently of the remaining countershaft units. The countershaft unitcan also be eliminated from the reversing transmission when necessary.Such a construction is conceivable, for example, for forklift truckswhich, as a rule, have only three different gears available. The spacegained by the removal of the countershaft unit can be used for a secondauxiliary output.

[0015] Accordingly, the instant invention makes it possible to considerthe most different transmission requirements while retaining the basictransmission draft. Thereby material and costs can be spared and thetransmission can be easily serviced. It is also possible to easily adaptan already existing transmission to new requirements.

[0016] The invention is explained in detail herebelow with reference tothe drawing which does:

[0017]FIG. 1 is a representation of a reversing transmission for shortcenter distances according to the prior art;

[0018]FIG. 2 is a transmission diagram of a reversing transmissionaccording to the instant invention;

[0019]FIG. 3 is a representation of the shaft arrangement of aninventive reversing transmission with short center distance;

[0020]FIG. 4 is a representation of the shaft arrangement of aninventive reversing transmission with long center distance; and

[0021]FIG. 5 is a diagrammatic representation of an inventive reversingtransmission with power divider transmission.

[0022] According to the prior art, FIG. 1 shows a reversing transmissionwhich is provided for small center distances. The countershafts of thecountershaft units for the forward gear KV, the reverse gear KR, thefirst gear K1, the second gear K2, the third gear K3 and the fourth gearK4 are disposed around the input shaft AN. At the same time, the shaftof the third gear serves as output shaft. In this shaft arrangementlittle space remains for being able to consider peculiarities ofdifferent installation situations since, due to the circulardistribution of the transmission shafts, little flexibility is left fora variation of the arrangement.

[0023]FIG. 2 shows a reversing transmission 1, according to the instantinvention, where the input power is transmitted by a torque converter 2to a hollow shaft 3 which constitutes the input shaft. Upon the hollowshaft 3 is placed a fixed gear 4 through which the input power isrelayed.

[0024] The transmission has countershafts 5, 6, 7 8 and 9 upon which arerespectively situated fixed gears, idler gears and clutch elements andwith these several countershaft units are formed. The countershaft unitfor the reverse gear KR is formed by the countershaft 5, the idler gear10, the clutch element 11 and the fixed gears 12 and 13. Thecountershaft unit of the forward gear KV comprises the countershaft 6,the idler gear 14, the clutch element 15 and the fixed gear 16. Thecountershaft unit for the first gear K1 is formed by the countershaft 7,the idler gear 17, the clutch element 18 and the fixed gear 19. Thecountershaft unit for the second gear K2 has the countershaft 8, theidler gear 20, the clutch unit 21 and the fixed gear 22. Thecountershaft unit for the third gear K3 is formed by the output shaft23, the clutch element 24, the fixed gear 25 and the idler gear 26. Thecountershaft unit for the fourth gear consists of the countershaft 9,the idler gear 27, the clutch unit 28 and the fixed gear 29. Thecountershaft unit K4 is preferably placed next to the input shaft 3, thefixed gear 4 meshing with the idler gear 27.

[0025] The mode of operation of the gear wheels and clutches forshifting the different gears and the corresponding power flow is wellknown to the expert. Therefore, it will not be further considered here.

[0026] By the torque converter 2 is preferably driven another hollowshaft 30 which serves an auxiliary input 31 situated far in front of thetransmission so that a hydraulic pump 32 needed for the vehicle or thetransmission can be disposed in parallel with the transmission. Theinstallation space needed for the transmission is thus further reducedby the axial length diminishing to a minimum measure.

[0027] The countershaft units KV, KR and K4 form a reversingtransmission unit 33 and the countershaft units K1, K2 and K3 form agear transmission unit 34 wherein the countershaft units of thereversing transmission unit 33 are provided on one side next to theinput shaft 3 and the countershaft units of the gear transmission unitattach to the countershaft unit KR of the reverse gear.

[0028] In FIG. 3 is diagrammatically shown the spatial distribution ofthe shafts of the inventive reversing transmission. Upon one side of theperiphery of the input shaft 3 are situated the countershaft units ofthe forward gear K4, those of the reverse gear KR and of the fourth gearK4 which form the reversing transmission unit 33. The countershaft unitKR is placed between the countershaft units KV and K4. The other side ofthe input shaft 3 remains free. The countershaft unit K4 can be easilyremoved from the arrangement in this design.

[0029] The countershaft units of the gear transmission unit 34 areattached on the free side of the countershaft unit of the reverse gearKR. The countershaft unit K3 with the output shaft 23 are placed betweenthe countershaft units K1 and K2. Accordingly, the gear transmissionunit 34 lies behind the reversing transmission unit 33 in relation tothe output shaft 3.

[0030] An auxiliary drive 31 is situated upon the free side of the inputshaft 3 opposite to the transmission units 33 and 34. A second auxiliarydrive (not shown in the drawing) can be provided instead of thecountershaft unit K4.

[0031] The axles of the shafts of the reversing transmission units KV,KR and K4 and the input shaft 3 form a quadrilateral 35 and the axles ofthe shafts of the gear transmission unit K1, K2, K3 and the shaft of thecountershaft unit of the reverse gear KR form one other quadrilateral36. Depending on the special demands on the reversing transmissionduring installation in a certain vehicle, the individual countershaftunits can be moved relative to each other, the two quadrilaterals 35 and36 changing their angles.

[0032] In FIG. 3, a shaft arrangement with short center distance betweenthe input shaft 3 and the output shaft 23 is shown. In FIG. 4, on theother hand, a shaft arrangement with long center distance is shown. Inthis embodiment of the inventive reversing transmission, thequadrilateral 36 is stretched in length compared to the embodiment ofFIG. 2. Thereby the output shaft 23 and thus the countershaft unit ofthe third gear K3 remove themselves from the countershaft unit of thereverse gear KR and a larger center distance results.

[0033] In FIG. 5, a reversing transmission is shown which is providedwith a power divider transmission 37 for bridging greater distances. Inthe shape shown, the power divider transmission has four shafts, but anyother design of power divider transmission can be used.

[0034] It is also possible to swing the gear transmission unit attachedto the countershaft unit KR within the free space on the periphery ofthe countershaft 5. In the same way, the reversing transmission unit 33can be swung along the periphery of the input shaft 3. In FIG. 4, thegear transmission unit 34, turned in direction of the countershaft unitK4, is shown by way of example. In this manner, the inventive reversinggear can be easily adapted to the structural pecularities of a vehicle.Reference numerals 1 reversing transmission 2 torque converter 3 inputshaft 4 fixed gear 5 countershaft 6 countershaft 7 countershaft 8countershaft 9 countershaft 10 idler gear 11 clutch element 12 fixedgear 13 fixed gear 14 idler gear 15 clutch element 16 fixed gear 17idler gear 18 clutch element 19 fixed gear 20 idler gear 21 clutchelement 22 fixed gear 23 output shaft 24 clutch element 25 fixed gear 26idler gear 27 idler gear 28 clutch element 29 fixed gear 30 hollow shaft31 auxiliary drive 32 hydraulic pump 33 reversing transmission unit 34gear transmission unit 35 quadrilateral 36 quadrilateral 38 powerdivider transmission KV countershaft unit forward gear KR countershaftunit reverse gear K1 countershaft unit first gear K2 countershaft unitsecond gear K3 countershaft unit third gear K4 countershaft unit fourthgear AN input shaft

1. Powershift multi-gear reversing transmission having one input shaft,one output shaft and several countershafts with idler gears, fixed gearsand gear clutches distributed thereon which form several countershaftunits (KR, KV, K1, K2, K3, K4) for gear and direction shiftings,characterized in that the individual shafts are combined to form onereversing transmission unit (33) (KV, KR, K4) and one gear transmissionunit (34) (K1, K2, K3), the gear transmission unit being provided on anyside of the input shaft (3) and said gear transmission unit (34)attaching to the reversing transmission unit (33) so that said reversingtransmission unit (33) and said gear transmission unit (34) are disposedin relation to the input shaft (3) in succession upon one side of saidinput shaft.
 2. Reversing transmission according to claim 1,characterized in that said gear transmission unit (34) is provided onany free place on the periphery of said countershaft (5) of said reversegear (KR).
 3. Reversing transmission according to claim 1 or 2,characterized in that said shafts (5, 6, 9) of said reversingtransmission unit (33) and said input shaft (3) form one rectangle (35)and the shafts (7, 8, 23) of said gear transmission unit (34) and oneshaft of said reversing transmission unit (33) form one other rectangle(36), the angles of said rectangles (35, 36) being variable. 4.Reversing transmission according to any one of the preceding claims,characterized in that a power distributor transmission (37) can beattached to the output shaft (23).
 5. Reversing transmission accordingto any one of the preceding claims, characterized in that thecountershaft unit of the fourth gear (K4) is placed next to the inputshaft (3) independently of the remaining countershaft units. 6.Reversing transmission according to any one of the preceding claims,characterized in that the countershaft unit of the fourth gear (K4) canbe removed from said reversing transmission (1) without further changes.7. Reversing transmission according to any one of the preceding claims,characterized in that parallel next to said input shaft (3) is situatedan auxiliary output (31).
 8. Reversing transmission according to any oneof the preceding claims, characterized in that said auxiliary input (31)is engine dependent.
 9. Reversing transmission according to any one ofthe preceding claims, characterized in that instead of the countershaftunit of the fourth gear (K4) an auxiliary output can be provided.